engleski

Measuring acoustic parameters of air-handling units

In this work acoustic parameters of air handling unit (AHU) have been determined according to international standards EN ISO 1886 and EN ISO 3744. Acoustic insulation of AHU casing has been measured by using the artificial sound source method described in EN ISO 11546-2. The artificial source has been designed to prevent vibrations to the floor of the model box with considered panels and excitating resonant frequencies of box where panels for the AHU casing are tested. The sound pressure levels in octave bands from 125 Hz to 8 kHz with and without enclosure has been measured in the surrounding of the model box in the specified microphone positions according to the envelope surface method described in the standard EN ISO 3744. After the measuring acoustic insulation of casing the inlet in-duct sound power level, outlet in-duct and airborne sound power levels have been determined with the aim to distinguish the radiated sound power in the space where air is delivered and where the central unit of AHU is located. The results of measuring inlet and outlet in-duct sound power levels have been compared with theoretical results knowing the parameters of the fan in the AHU.

air handling unit; acoustic insulation of casing; artificial sound source; insertion loss; inlet; outlet and airborne sound power levels

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